Design of an Inductor-less Step-Down AC/AC Converter Combined with a Symmetrical-Type Converter and Ladder-Type Converters

In this paper, a new inductor-less step-down ac/ac converter is designed by using switched-capacitor (SC) techniques. Unlike existing inductor-less ac/ac converters, the proposed ac/ac converter consists of ladder-type converters nested in a symmetrical-type converter. In the proposed ac/ac converter, the 1/4× voltage gain is achieved by converting an ac input twice by the symmetrical-type converter and the ladder-type converters. The proposed new topology enables to reach not only high power efficiency but also high input power factor. To evaluate the characteristics of the proposed ac/ac inverter realizing the 1/4× voltage gain, we conducted theoretical analysis and simulation program with integrated circuit emphasis (SPICE) simulations. The SPICE simulation results demonstrated that the proposed ac/ac converter can achieve about 84% power efficiency and 0.88 input power factor when the output power is 200W.